#include <iostream>
using namespace std;

int main() {
    string s;
    cin >> s;
    int n = s.size();
    
    for (int i = 0; i <= n/2; i++)
    {
        if (s[i] != s[n-i-1]) {
            cout << "no";
            return 0;
        }
    }
    cout << "yes";
    
    return 0;
}